There is a plugin for iPhoto that lets you upload directly to Facebook albums.
Yes, I use it, I think up to 200 max at a time.
Just be careful not to do ANYTHING to the FB album iPhoto creates in iPhoto.
If you do, any comments in FB will be lost, and also FB image tags. I learned the hard way, uploaded K-6th grade photos to our class 30th FB reunion site, and people had fun tagging other people. When I moved that photo in iPhoto all the tags and comments were lost in FB.
You are forewarned.